Clinical presentation of onchocerciasis among indigenous and migrant farmers in southwest Ethiopia

Abstract

Objective: To show the magnitude of the problem and give a systematic account of the clinical manifestations of onchocerciasis in a rain forest ecology in southwest Ethiopia.

Design: A cross sectional clinico-epidemiological study.

Setting: Teppi Health Centre and Endris-Goji Clinic, Ethiopia.

Subjects: Four hundred and twenty one individuals aged ten years and above.

Results: Eighty four per cent of the examined people had a macrofilarial load ranging from one to 855 microfilariae per mg of skin snip. If the presence of any of skin microfilaria, nodule and/or leopard skin were taken as diagnostic criteria, the overall prevalence rate of onchocerciasis would be 88%. However, if we strictly followed stringent diagnostic criteria such as presence of unprompted itching, nodule(s), microfilaraedermia and skin dermatitis, the prevalence rate of onchocerciasis would be 23% (98/421). Hanging or pendular scrotum, which has been rarely reported in Africa but not until now in Ethiopia, was found in 19% (46/246) of the male patients. There was neither negative nor positive correlation between microfilarial load and severity of clinical manifestations of the disease.

Conclusion: Onchocerciasis has been found to be one of the major health problems in this community and its diagnosis should not be based on selected signs and symptoms such as nodules and leopard skin alone that could undermine the magnitude of the problem.